1. Field of the Invention
The present invention relates to an electronic camera, a solid-state image pickup device, and a driving method for a solid-state image pickup device which can be used for, for example, a digital camera having a CCD.
2. Description of the Related Art
Conventionally, in CCDs (Charge Coupled Device) which have been most generally used as solid-state image pickup devices, at the time of photographing a strong light source, during a period of time when electric charge signals obtained by photoelectric conversion by PDs (photodiodes) provided in units of pixels are being read onto vertical CCDs which are transfer lines and are being sequentially transferred, electric charges are further superposed at the vertical CCDs which should be shielded. In addition thereto, the electric charges accumulated at the vertical CCDs are not entirely transferred and are remained, and as a result, there are cases in which a phenomenon called “smear” that a light stripe appears vertically in an obtained image is brought about.
In order to prevent smear, it is most effective to mechanically shield all over the light receiving surface of the CCD after an exposure timing by a mechanical shutter. However, at the time of moving picture mode in which image pickup of, for example, about ten frames through thirty frames per one second is successively carried out, the above-described mechanical shutter cannot be used.
Further, as another technique for preventing smear, it has been considered that, in an operating mode in which output signals of a CCD solid-state image pickup device are used for processings for various control systems, an electric charge sweeping-out pulse is applied to a substrate of the CCD at every period of all of horizontal blanking at least within a vertical synchronizing period after light receiving at a plurality of sensor units, and immediately before reading signal charges from the plurality of sensor units to vertical CCDs, the vertical CCDs are driven to transfer at a high speed in order to sweep out the electric charges in the vertical CCDs.